Penn State Master Gardeners, Pat Welfley of Newport and Mindy Wenger of Carlisle, are my guest columnists for this week. Pat and Mindy evaluated annual flowering plants growing this season in the Penn State Master Gardeners’ Trial and Idea Garden, located at the corner of Claremont Road and Army Heritage Drive on the grounds of Claremont Nursing and Rehabilitation Center near Carlisle. Mindy and Pat selected a mix of new-to-the-market and tried-and-true varieties for trialing and evaluation. Here is their report:

Despite being high and dry for much of the summer, our trial gardens looked beautiful from planting in May through first frost in October. A few of our annuals struggled, but others survived and even thrived, in the full sun and high temperatures of mid-summer. It seemed that if a plant was good, it was very, very good, and if it was bad, it was very, very bad, with few between.

The plants were evaluated for their flowers, foliage, uniformity, and overall appearance; the numbers were added and then averaged for each plant. The report begins with the highest-scoring plant.

Begonia ‘Yin Rose’

Begonia "Yin Rose" was pleasing from the beginning. Its small but stunning pink flowers and reddish foliage put on a show worthy of a winner. The 12- by 14-inch mounding habit makes it easy to plant amongst other flowering plants or by itself en masse. And best of all, it never required deadheading.

Alternanthera ‘Little Ruby’

Alternanthera "Little Ruby" was all foliage and no flower, but oh, what a show it put on. It was a carefree 4-foot square mass of deep burgundy leaves which paired easily with the other plants in the garden. It delightfully outgrew our expectations in both size and appearance; just make sure you give it lots of space to grow and you won’t be disappointed.

Lantana Bandana Red

Lantana Bandana Red came in only slightly lower in the ratings because the flowers took their time to get going. But it didn’t take long for it to become a prolific bloomer, growing almost shrub-like with its 30-inch spread and 19-inch height. It delighted not only us but also the many butterflies that visit the gardens throughout the summer.

‘Calico’ Ornamental Pepper

"Calico" Ornamental Pepper was a fun surprise for us with its purple, cream, and green variegated leaves and brilliant red miniature peppers. It added a unique color display and created a conversation piece for all who passed by. Its array of colors and compact size, growing only 14 inches tall by 21 inches wide, make it easy to mix with other annuals in either containers or beds.

Illusion Emerald Lace Sweet Potato Vine

Illusion Emerald Lace Sweet Potato Vine is another all-foliage plant. It’s a new cultivar for 2012, so ideal for evaluating in our trial garden. It got off to a late start, but boy, did it catch up. By the middle of August it had spread into an 8-foot square mass of stunning lime-green lacey leaves. It hugs the ground, spreading to cover anything in its path, and makes a beautiful ground cover; but give it room to spread.

Melampodium ‘Lemon Delight’

Melampodium "Lemon Delight" was another of our delightful surprises this year, giving us a continuous floral display of yellow that never required deadheading. It mounded nicely at 22 by 23 inches, almost a perfect sphere. The plants were very uniform in color and size with at least (we stopped counting) 100 flowers per plant.

Salvia ‘Victoria Blue’

Salvia "Victoria Blue" came out strong, stayed strong and finished in the top. It flowers early, holds its color throughout the summer and continues blooming well past the first frost. It takes the long hot dry summer and gives back an unending supply of purplish blue spiky flowers that delight pollinators and viewers alike.

Snow Princess Sweet Alyssum

Again this year we planted Snow Princess Sweet Alyssum. It was such a big hit last year that we just needed to plant it again this year. It didn’t disappoint us in any way, bringing in the pollinators and spreading into a gorgeous 17- by 25-inch mass of tiny white flowers. This plant also needs room to spread. It did peter out a bit at the end, but still overall was a frontrunner.

Zinnia ‘Profusion Yellow’

Another tried and true plant is Zinnia "Profusion Yellow," with bright yellow flowers from late spring until late summer. Deadheading is helpful but not necessary. When we measured these plants, they were 16 inches tall and 28 inches wide with close to 100 flowers on each plant.

Cherry Red Marguerite Daisy

Cherry Red Marguerite Daisy was a real disappointment. It started out strong, receiving rave reviews, even with the need for deadheading, for about the first 4 weeks. Then it started a downward spiral that never ended; the flowers just stopped blooming. The leaves stayed nice for a few more weeks, but eventually, they too gave up and died out.

Angelonia Archangel Pink

Another plant that started out well and ended poorly was the Angelonia Archangel Pink. While it was blooming, it rivaled the salvia; the two together created a beautiful show of spiky purple and blue flowers. Shortly after the first month ended, however, the Angelonia flowers began fading until they eventually stopped blooming. A few of the plants were completely over taken by the sweet potato vine, so possibly we didn’t have enough plants for a true trial.

Gazania ‘New Day Clear Orange’

Gazania "New Day Clear Orange" did not live up to expectations either. The few flowers that did show didn’t have a long bloom time and required deadheading. The foliage looked nice for the first few weeks, then just looked sad. The plants eventually grew to 12 inches wide but only reached 8 inches in height.

Pentas, Verbena, and Cosmos

Pentas, Verbena, and Cosmos all came in at the bottom of the pile and in that order. They all did virtually the same thing...and it was not good. Pentas New Look White started out uniformly bad, peaked a bit from the middle of July to mid-August, then took a nose dive. The flowers were never plentiful or showy. The plants grew to 1 foot high and wide but never thrived in our garden.

Verbena Tukana Scarlet

Verbena Tukana Scarlet spread up to 28 inches wide, but the foliage as well as the flowers always looked sporadic and dismal. The flowers, although a showy red, were sparse and required deadheading. Even though most of the plants looked as if they were constantly near death, they held out to the end, struggling every step of the way.

Cosmos ‘Sonata Mix’ and ‘Sonata White’

Finally, Cosmos "Sonata Mix" and "Sonata White," both of which started out very promising, ended up being the biggest disappointment of all. From the very beginning, extensive deadheading was necessary and by mid-July, several of the plants died out. They never recovered and eventually had to be or should have been cut out early in the season.

Outbrain